Leonardo DiCaprio to play Alan Turing?

I hadn’t realised this before (update: err, actually I did – I wrote about this in October 2011 too, oops) but apparently Leonardo DiCaprio is to play Alan Turing in “The Imitation Game“, a biopic.

Leonardo DiCaprio at the Body of Lies film pre...
Leonardo DiCaprio at the Body of Lies film premiere in London (Photo credit: Wikipedia)

It’s fantastic news, not just because the idea of the film itself is appealing but because DiCaprio is surely one of the greatest film actors of this or any other generation. I sense that he’s never quite had the recognition he deserves because his first big role, in Titantic, was rather soft and slushy, but he is so good that even when he is in an otherwise mediocre film – J Edgar is a recent example – he lifts it to a higher plane.

The Great Alan Turing

Allan Turing Statue, on display at Bletchley Park
Image via Wikipedia

Slashdot have a story to the effect that Leonardo DiCaprio is to play Alan Turing in a film that will mark the mathematician’s centenary next year.

Great news – the man’s memory deserves nothing more than the actor who has proved himself to be both great and edgy in recent work (he’s certainly not the milque toast figure the start of his career briefly suggested.)

As a geek, of course, I hope that the film will try to explain, just a little his achievements.

But how can you explain the ideas of computability and the Church-Turing thesis in a popular film? A tough one, but I suppose you could do something.

The Bletchley Park “bombe” and the idea that the weakness of the German Enigma machine – that it would never map a letter to itself (eg., in any message “e” would never be encrypted as “e”) – could be used to break the code (if a combination of a guessed plain text, usually a weather report, at the start of the message , and the initial key settings produced code that mapped letters to themselves then the initial settings were wrong) – is probably easier to explain.

And don’t forget about SIGSALY, the voice encryption system Turing worked on with Bell Labs. As a piece of engineering this is probably impossible to over-estimate in importance: as the first practical pulse code modulation system it could even be said to be the mother the mobile phone, or at least its grand aunt.

And, of course, let me again plug my book of the year: The Annotated Turing: A Guided Tour Through Alan Turing’s Historic Paper on Computability and the Turing Machine